Optus officials have pitched the data sharing plans as a major announcement that will peel cost-conscious customers from its major rival Telstra.

While Telstra also allows data sharing, it charges $10 per month per device for the privilege. Under the new Optus plans, customers pay a one-time fee of $5 per device — there are no ongoing charges.

However, starting next year, Telstra will provide access to an expanding public Wi-Fi network free to Bigpond broadband customers (limited by the customer's fixed broadband data limit). And iiNet so far has not charged for access to its own announced public Wi-Fi networks in Adelaide and Canberra.

Optus chief country officer Paul O'Sullivan said Optus will be giving up revenue with the new plans, but that he believes the sacrifice will result in customer gains.

"Yeah, we sacrifice some revenues in the short term, but we're very confident this will drive our business in the medium term."